Montreal Yo-Yo Gas Prices Unjustified

It's good to see gas prices down, but those annoying spikes that see prices jump by ten cents in a day seem a bit over the top. This price volatility doesn't seem justified and I set out to see if it exists elsewhere. The people over at gasbuddy have all sorts of graphing tools and I've created one that compares Montreal gas prices to those in Syracuse and Miami. Aside from the striking difference in price look how stable and gradual price movements are in the US. The pattern here is a large jump followed by a gradual decline. My research indicates that this pattern occurs all across Canada, but not in the USA. I think our retailers have some explaining to do...
You can beat these spikes by filling up regularly when the price is stable. Then you can ride out the couple of days after a spike, until the price falls.
If you use 'Super' gas, ULTRAMAR gives you a 3 cent break on Thursday, regardless of price. If you have a Costco card, the downtown location at Bridge street now sells gas at prices that are always at least 5 cents cheaper.